1. Field of the Invention
This invention relates to a vehicle including a first motor, a second motor, and an engine as drive sources.
2. Description of Related Art
Japanese Patent Application Publication No. 2008-265598 (JP 2008-265598A) discloses a vehicle including a planetary gear mechanism to which a first motor, a second motor, and an engine are coupled and a clutch that fixes an engine shaft, wherein fixing the engine shaft with the clutch enables the vehicle to travel using power of at least one of the first motor and the second motor without using power of the engine (hereinafter, referred to as “motor travel”).
The vehicle disclosed in JP 2008-265598A is capable of switching between engine travel that uses the power of the engine and motor travel that does not use the power of the engine. In addition, during motor travel, the vehicle can switch between dual motor travel that uses power of both the first motor and the second motor and single motor travel that only uses power of one of the first motor and the second motor. Supplying cooling oil to both the first motor and the second motor without taking these modes (engine travel, dual motor travel, and single motor travel) into consideration may possibly cause an unnecessary increase in loss (so-called drag loss) attributable to viscosity of the cooling oil.